The purpose of this study is to examine fetal growth patterns using longitudinal measurements throughout pregnancy of: (1) symphyeal-fundal heights; (2) weight gain at each prenatal visit; (3) serial biparietal and chest diameter measurements from ultrasound. Linear regression models have been fit to the serial symphyseal-fundal height measurements after stratifying the sample mothers according to the outcomes of their pregnancies in terms of small-, appropriate-, or large-for-gestational age births. Using a robust analysis of covariance procedure, additional factors (e.g., cigarette smoking, alcohol intake, low maternal prepregnancy weight, etc.) will be tested for significance in modifying intrauterine growth patterns.